U.S. Pat. No. 3,060,191 and U.S. Pat. No. 3,880,812 disclose poly(alkylene trimellitimides) which are based on trimellitic anhydride (TMA) and aminoalcohols containing 2 to 12 carbon atoms. U.S. Pat. No. 3,944,706 discloses use of poly(ethylene trimellitate imide) as a wire top coat varnish. Essentially all examples are based on the ester imide formed by reaction of TMA with ethanolamine (EA). U.S. Pat. Nos. 3,458,480; 3,459,829; 3,562,219; 3,697,471; 3,929,714; 4,145,334; 4,267,232 and 4,145,351 disclose poly(ester-imides) based on TMA and aliphatic aminoalcohols. All examples are based on TMA and ethanolamine and, in addition, the examples in these patents all contain multifunctional compounds which are required to thermoset the polymers. U.S. Pat. No. 3,793,250 discloses poly(ester-imides) based on TMA and aliphatic aminoalcohols but these polymers also contain the lactam ring. Poly(ester-imides) and an improved process for making the polymers are also disclosed in U.S. Pat. No. 4,245,086. Poly(alkylene trimellitimide) poly(ester-imides) are also disclosed in U.S. Pat. No. 4,012,555 where the polymers are blended with poly(alkylene diimides). Again, all examples are based primarily on the poly(ester-imide) formed by reaction of trimellitic anhydride with ethanolamine.
U.S. Pat. No. 3,880,812, discloses poly(ester-imides) of high molecular weight and processes for preparing the polymers. According to column 3, lines 19-22, "n-hydroxyethyl trimellitic acid imide is the preferred imide" and "preferably comprises at least 90 mol % of the mer units of the polymer." Also, in column 3, line 29 ff, it is disclosed that copolymers "with 10 to 20% of a higher hydroxyalkyl trimellitic acid imide have 20.degree. to 40.degree. C. lower heat deflection temperature than the preferred homopolymer."